Is there a way using JavaScript or jQuer开发者_JS百科y to detect if a confirm or alert box is being displayed?
If you wanted to run some code when an alert()
fires, you could try something like this:
I've only tested in Chrome, so I'm not sure about browser support.
Example: http://jsfiddle.net/Q785x/1/
(function() {
var _old_alert = window.alert;
window.alert = function() {
// run some code when the alert pops up
document.body.innerHTML += "<br>alerting";
_old_alert.apply(window,arguments);
// run some code after the alert
document.body.innerHTML += "<br>done alerting<br>";
};
})();
alert('hey');
alert('you');
alert('there');
Of course this only lets you run code before and after an alert. As @kander noted, javascript execution is halted while the alert is displayed.
No there is not. You can check that the return value of a confirm
command is indeed true
or false
but you cant check whether there visually there.
These things are part of the browser not part of the DOM. I'm sure there's a dirty hack that works for IE because it's a bastardized child of the windows OS.
You could do this if you want to...
(function () {
// remember the normal alert
var oldAlert = (function(){ return this.alert; }()),
oldConfirm = (function(){ return this.confirm; }());
// inject ourself into the window.alert and window.confirm globals
alert = function (msg) {
oldAlert.call(document, msg);
document.onAlert(msg);
};
confirm = function (msg) {
var result = oldConfirm.call(document, msg);
document.onConfirm(msg, result);
return result;
};
// these just chill and listen for events
document.onAlert = function (msg) {
window.console && console.log('someone alerted: ' + msg);
};
document.onConfirm = function (msg) {
window.console && console.log('someone was asked: ' + msg);
window.console && console.log('and they answered: ' + (msg ? 'yes' : 'no'));
};
}());
The downside to this is that
- you're hacking a host method of a browser (stuff you shouldn't typically do - http://perfectionkills.com/whats-wrong-with-extending-the-dom/)
- you should just be better keeping track of your
alert()
confirm()
usage, haha
Confirm and alert boxes are blocking events - Javascript code execution is halted while these are displayed. So no - you can not detect if one is currently being displayed, as far as I know.
If you want to detect if these are being blocked. You will have to do your own thing with the message you will be dispalying but override the native alert/confirm.
window.nativeAlert = window.alert;
window.alert = function (message) {
var timeBefore = new Date();
var confirmBool = nativeAlert(message);
var timeAfter = new Date();
if ((timeAfter - timeBefore) < 350) {
MySpecialDialog("You have alerts turned off, turn them back on or die!!!");
}
}
window.nativeConfirm = window.confirm;
window.confirm = function (message) {
var timeBefore = new Date();
var confirmBool = nativeConfirm(message);
var timeAfter = new Date();
if ((timeAfter - timeBefore) < 350) {
MySpecialDialog("You have alerts turned off, turn them back on or die!!!");
}
return confirmBool;
}
Obviously I have set the time to 3.5 milliseconds. But after some testing we were only able to click or close the dialogs in about 5 milliseconds plus
To add to @user113716's answer you can rely on time. I assume that if confirm dialog took less than 200 ms, it is blocked by browser. Below I return true if confirm dialog is blocked (by default it returns false, the code is in TypeScript).
let oldConfirm = window.confirm;
window.confirm = (msg) => {
let time = new Date().getTime();
let conf = oldConfirm(msg);
return new Date().getTime() - time > 200 ? conf : true;
}
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